Help me find this manga?

aggghhh~~~ i didn't bookmark it! -_- it was about a girl who had this childhood and at school he's really cool but with her, he acts like a coward. uhhh that's basically the gist the of the story. he shows his true colors when she mentions getting a boyfriend and then he gets all aggressive and forces a kiss on her. can someone help me find it asap?! i really want to read it again! >.<